This invention relates to a circuit arrangement for controlling the operating functions, for example, of a broadcast receiver, in which an up/down counter is associated with each operating function, of which the particular count corresponds to a certain setting of the operating function and which comprises an up-counting input and a down-counting input and, in dependence upon function control signals at these inputs, counts pulses supplied by a clock-pulse generator.
In modern broadcast receivers, such as radio broadcast receivers or television broadcast receivers, operating functions, such as volume, brilliance, colour saturation and the like, can be controlled by means of so-called touch keys. For adjusting volume for example, two touch keys are present, one for "louder" and one for "softer". An up/down counter is associated with this "volume" operating function, its particular count corresponding to a certain volume setting. One such counter is also associated with each of the other operating functions. If, in the case of the "volume" operating function for example, the touch key for "louder" is operated, a binary control signal is delivered to the up-counting input of this counter, causing the counter to count clock pulses delivered to it from a clock-pulse generator in the up direction for as long as the touch key is touched. The resulting increase in the count leads to an increase in volume. Conversely, if the touch key for "softer" is touched, a binary control signal is delivered to the down-counting input of the counter, causing the counter to count the clock pulses in the down direction which leads to a reduction in the count and, hence, to a reduction in volume. If neither of the two touch keys is touched, the count remains unchanged so that there is also no change in volume. As can be seen, at least two inputs are required on the up/down counter for controlling the three functions of up-counting, down-counting and standstill.
In order to simplify the structure, it is desirable to accommodate the entire control circuit as far as possible in a single integrated circuit. A major problem in the construction of complicated integrated circuits such as these is that only a limited number of connecting pins is available on the circuit housing. For each up/down counter associated with an operating function, it is necessary to provide one up-counting input and one down-counting input solely for controlling the counting mode of the counter. In view of the relatively large number of operating functions required for a broadcast receiver, this would lead to a large number of connecting pins on the housing of the integrated circuit which would involve considerable costs. In view of the intended application, however, costs such as these are unacceptable.
In addition to or as an alternative to the possibility of controlling the operating functions through touch keys, the operating functions may also be remote-controlled. In this case, the remote-control generator transmits signals which are decoded in the remote-control receiver in the broadcast receiver and produce the same effect as depression of the corresponding touch keys for the required operating function. Accordingly, the above-mentioned problem concerning the number of connecting pins also exists in cases where the operating functions are remote-controlled.
The object of the present invention is to construct a circuit arrangement of the type referred to above in such a way that it may be produced in the form of an integrated circuit at reasonable cost.